Please refer to FIG. 1, which is a lens adjusting apparatus 10 disclosed in U.S. Pat. No. 5,895,110. A fixed board 12 is disposed perpendicular to a base 11 to form a L-shape. Then a U-type supporting plate 13 is disposed on the fixed board 12, and the U-type supporting plate 13 faces upward with gaps on both sides between the-U type supporting plate and the fixed board 12 in order to form a sliding groove 131. There is a hinge 14 disposed on one upper corner of the fixed board 12. Then a projection lens module 16 is equipped on one end of the sliding unit 15 that has a screw nut 17 firmly matched to the hinge 14. The sliding unit 15 is inserted into a sliding groove 131 from the opening of the supporting unit 13, and the adjusting rod 18 passes through the hinge 14 and is screwed to the screw nut 17. When the adjusting rod 18 is rotated, the screw nut 17 pushes forward the projection lens to shift up and down along the adjusting rod 18.
As commonly known, the following process makes up a conventional adjusting apparatus 10. By using either the punching or the casting way, the base 11, the fixed unit 12 and the supporting unit 131 can be one body for the first assembly component. The sliding unit 15, the projection lens set 16 and the screw nut 171 can be one body for the second assembly component. And then these two components can be assembled as the adjusting apparatus 10 through the adjusting rod 10. However, when we install the second assembly component into the opening of the supporting unit 13, the hinge 14 will stop it and cause the difficulties of assembly. In addition, by considering the manufacturing deviation of the hinge and screw nut, and the assembly deviation of the sliding unit and the supporting unit, there will be much difficulties when assemble the adjusting rod and then the adjusting rod is not able to be parallel to the z-axis and then causes the obliquely movement of the projection lens set. Therefore, in order to guarantee that the adjusting rod is accurately established, we must enhance the processing and assembly precision that will increase the processing cost.
Moreover, because the adjusting apparatus 10 is assembled with the projection lens set 16, when the adjusting unit 10 is damaged and must be repaired or replaced, the whole set of adjusting apparatus 10 with projection lens set 16 have to be replaced together. This will cause either the waste of the projection lens set 16 or the waste of time to dismount the projection lens set 16 and then replace the other adjusting components. However, the projection lens set 16 is the extremely precise optical part and it will be easily damaged in the disassembly process. Therefore, the conventional adjusting apparatus has a problem that it is inconvenient to repair.